Ceiling Fan Motor Circuit Diagram

 

    Generally, the ceiling fan motors are split phase single phase AC motors. There are two windings inside the ceiling fan known as Starting Winding and Running Winding. Starting Winding is also known as Auxiliary Winding while Running Windings is known as Main Winding.

     Due to  the single phase supply, there is only one revolving flux which rotates in clockwise and then anti-clock wise direction simultaneously. In other words, the direction of motor rotation changes after each of the half cycle (AC sine wave) which leads the rotor to rotate in clock wise and anti-clock wise continuously. According to the double field revolving theory, both torque cancels out each other after a half cycle. The resulting (net) rotating magnetic field would be zero i.e. zero starting torque. This is why a ceiling fan as well as single phase induction motors are not self-starting.

What is the Function of Capacitor in a Ceiling Fan?

We know that a ceiling fan can’t be started in single phase AC supply, but what magic a capacitor do in these motors to make itself starting.

According to double field revolving theory, an alternating flux can be divided into two fluxes which rotates initially in opposite direction. i.e. a single phase induction motor can be started by adding an auxiliary winding and a capacitor connected in series to it.

To start a single phase AC induction motor, two phases are needed to produce the rotating magneto motive force (MMF) but we have only one phase due to single phase AC supply in our homes. Therefore, we need an additional phase to start these kind of motors. We obtain the second phase by adding a capacitor in series with the starting wind of a ceiling fan motor.

                                                                                    By

                                                                                    Sri J,Jagan Rupchand. M.E.,

                                                                                    Lecturer / EEE